1. Field of the Invention
This invention lies in the field of the drilling of large-diameter, deep boreholes by the rotary method.
More particularly this invention concerns means for overcoming the troubles normally exhibited when very large diameter bits and drill collars are supported on large-diameter drill pipe, whereby there may be a tendency for the tool joints to tighten to the point where they cannot be broken, or conversely, to loosen to the point where they separate; or, allows for transmission of torque through a tool joint without requiring full make-up of a given tool joint.
This invention involves apparatus for attachment to the tool joints whereby hydraulic pressure is provided to wedges which are retained between a cylindrical retainer ring, and the outer surfaces of the tool joint parts, so that independent relative motion of one part of the tool joint with respect to the other is prevented.
2. Description of the Prior Art
In the drilling of large diameter boreholes, which might be in the neighborhood of 10 to 20 feet or more in diameter, relatively large diameter drill pipe is required which may be of the order of 12 to 20 inches in diameter. Large torques are required to make up the tool joints to the proper torque.
In operation, because of the great mass of the bit assembly and of the drill collars, required to provide a pressure of the bits against the rock, and because of the resistance of the bit, the rotation may tighten the tool joints so that they lock, and it becomes impossible to separate them.